Holding means for instruments



United States My invention relates to holding means for electricalinstruments, and particularly to holding means for instruments, such asrelays of the type having movable parts for effectively locking themovable parts against movement during shipment or handling of the relayto prevent damage which might otherwise result from such handling orshipment.

More particularly, my present invention relates to holding means forlocking against movement the thermal element of a thermal relay,employing for the control of signaling devices used in connection withrailway signaling systems, a bimetallic strip heated by a heater elementfor actuating contacts at the expiration of a predetermined timeinterval after the application of power to the relay.

One well-known form of thermal relay employs a first bimetallic stripsupported through the medium of an oppositely disposed bimetallic stripwith the first strip carrying a heating element and the first stripbeing so disposed relative to an adjacent contact strip that the heatgenerated by the heating element causes the first strip to deflect in adirection toward the contact strip, the period of time preceding theengagement of the first strip with the contact strip being predeterminedgenerally in accordance with the initial position of the first striprelative to the contact strip.

Thermal relays of the type described are frequently employed in railwaysignaling circuits to provide a predetermined time interval between thefunctioning of related circuits of the system. It will be apparent thatwhen thermal relays are so used it is essential that there be littlevariation between the predetermined time interval selected duringmanufacture and assembly of the relay and the actual time interval ofthe relay during operation following the shipment and installationthereof. Unless some means are provided to prevent the thermal elementof the relay from experiencing excessive oscillatory movement duringsuch handling of the relay, damage may result to the thermal element tocause, for example, an undesirable variation from the predetermined timeinterval, which damage would otherwise be prevented if the thermalelement were held relatively fixed when the relay is not in use.

One object, therefore, of my invention is to provide improved holdingmeans which, when used in connection with a thermal relay, effectivelylocks the thermal element thereof from harmful movement without bendingor stressing the thermal element to avoid disturbing the timecalibration of the relay.

Another object of my invention is the provision, in a thermal relay, ofa mounting device, in which device the rotary motion of a driving screwis translated into linear motion of a pin for preventing excessiveoscillatory movement of a sensitive element which is to be protected.

Still another object of my invention is to provide novel holding meanswhich is effective for preventing the delicate and movable parts of arelay from undergoing harmful and injurious movement.

Yet another object of my invention is to provide improved holding meansfor protecting during shipment or handling the delicate parts of aninstrument, which means is relatively inexpensive to manufacture andassemble.

Other objects and characteristic features of my invention will becomeapparent as the description proceeds.

atent ice In accordance with my invention, and to attain theaforementioned objects, I provide holding means for cooperating with athin strip member carried by the bimetallic element of a thermal relay,said holding means including a housing secured to the base of a covermember of the relay, a pin disposed in the housing and verticallymovable between extended and retracted positions and provided withbifurcated portions at its one end nearest to the thermal element,biasing means for biasing the pin toward its retracted position, and adriving screw adjustably mounted in the housing and accessible from theexterior of the relay for driving the pin toward its extended positionin which the bifurcated portions of the pin extend on either side of thestrip member to prevent excessive lateral movement of the bimetallicelement.

I shall described one form of relay having applied thereto one form ofholding means embodying my invention, and shall then point out the novelfeatures thereof in claims.

In the accompanying drawings:

FIG. 1 is a side elevational view partially in section showing one formof holding means embodying my invention applied to a thermal relay.

FIG. 2 is a front elevational view of the relay shown in FIG. 1 withcertain of the parts removed, the holding each of the several views.

Referring to the drawings, the relay 10 comprises an L-shaped framemember 12 of suitable non-magnetic material, such as aluminum. The framemember 12 consists of a vertical portion 12a and a horizontal forwardlyextending portion 12b. A contact block 13 is secured to portion 12a offrame member 12 as by screws 13a, and a transparent cover member 14 isin turn secured to contact block 13 and portion 12b of frame member 12by means of suitable screws 16. A-top plate 18 of suitable insulatingmaterial, such as Bakelite, is secured to the portion 1212 at theunderside thereof by screws 20. The top plate 18 supports inverticaldepending relation three downwardly extending contacts whichinclude a fixed front contact 22, a thermal element TE, and a fixed backcontact 24.

The construction and arrangement of front contact 22, back contact 24and the thermal element TE are described and claimed in Letters Patentof the United States No. 2,371,018, granted to Harry E. Ashworth andSelden B. .Aylsworth on March 6, 1945, for Thermal Relay. Inasmuch asthese parts by themselves form no part of my invention, it is deemedunnecessary to describe them herein in detail, and only so much of thestructure of these parts will be described as is necessary for a fullunderstanding of the holding means embodying my invention.

As will be obvious from an inspection of the drawings, the front contact22 and back contact 24 are each provided with suitable means foradjusting their positions relative to thermal element T-E to enable thedesired time calibration to be obtained. The thermal element TEcomprises a main bimetallic strip 26 secured at its upper end to anoppositely disposed auxiliary bimetallic strip 28. Auxiliary strip 28 inturn is rigidly fastened to a rigid strip 30 secured by means, notshown, to top plate 18. The main strip 26 is provided at its lower endwith an insulating block 31 carrying a low resistance contact member 32for cooperation with back contact 24, a low resistance contact member 34for cooperation with front contact 22, a .thin rectangular metallicstrip 35, the ends of which extend outwardly from block 31 at itsopposite sides for a purpose which will be made clear as thespecification proceeds. Front contact 22, back con-tact 24, and contactmembers 32 and 34 are provided with flexible connectors 36, 38, 40 and42, respectively. The flexible connectors 36, 38, 40 and 4-2, and twoaddition-a1 flexible connectors 44 and 4-6 to be hereinafter described,are intended to be connected at their free ends to suitable contactstrips 47 provided in contact block 13.

The main strip 26 carries a heating element 52 insulated from strip 26by suitable insulating means such as, for example, a layer of asbestosnot shown. The heating element 52 is provided with a pair of electricalterminals not shown which are intended to be connected to flexibleconnectors 44 and 46 by means of rivets 54 and 54a (FIG. 2) mounted inthe insulating block 31 adjacent the opposite sides thereof.

When the parts are at ambient temperature, the contact member 32 engagesback contact 24 to close the contact 3224, and contact member 34 isspaced from front contact 22 so that contact 3422 is open. When heatingelement 52 is energized, the heat is transferred to strip 26 byradiation, and this heat causes the strip 26 to defiect in a directiontoward front contact 22 to open contact 3 2-24 and to close contact34-22. These positions of the contacts when heating element 52 becomesenergized are fully illustrated in the previously mentioned referencepatent. The opening of contact 32-24 will occur at the expiration of a'very short time interval after heating element 52 becomes energized,but contact 34 22 will not become closed until the expiration of arelatively long time interval after heating element 52 become-senergized.

In accordance with my present invention, 1 protect thermal element TEfrom becoming damaged due to excessive vibration during shipment orhandling of relay by providing a locking pin 56 having bifurcatedportions 562: and 56b. The bifurcated portions 56a and 56b of pin 56 areprovided adjacent their tipped ends with inner chamfers 56c and 56d,respectively, and pin 56 is so disposed relative to the strip 35 thatduring periods when relay 10 is not in operation pin 56 may be operatedto an extended position in which the bifurcated portions 56a and 56!)thereof are disposed closely adjacent both sides of the strip 35substantially as shown in FIG. 3, and in a manner now to be described.

Referring now to FIG. 3, the pin 56 is mounted in a tubular housing orcasing 58, which housing 58 is provided with a vertical hole 58a forreceiving pin 56. A lower portion 58b of housing 58 of slightly reduceddiameter extends outwardly of relay 10 through a hole 60 provided in thebase of cover member 14, the lower portion 5812 being formed with anannular split pin 58c rolled back to engage the underside of covermember 14 in a manner to firmly afiix the housing 58 to relay 10. Thehousing 58 is provided with an internal screwthreaded hole 58d whichextends vertically from the exterior of relay 10 to the base of theother hole 58a in the housing. A driving screw 62 concentric to pin 56extends upwardly through the screw-threaded hole 58d and abuts at itsupper end against an annular shoulder 64 integral to pin 56. By rotatingscrew 62 in the proper direction, pin 56 may be operated to an extendedposition in which it is shown in FIG. 3 for at times preventing lateralmovement of thermal element TE and a retracted position to becomedisengaged from the strip 35, or at other times permitting normaloperation of the relay. To limit the movement of pin 56 toward itsextended position, the housing 58 is provided adjacent its upper endwith aligned transverse holes 66 (FIG. 4), which holes are adapted toreceive the spread-apart ends of a pin 68 located with respect to pin 56such that it is always disposed between the bifurcated portions 56a and56b. It will be noted that pin 56 is guided by the pin 68 as pin 56moves toward its extended position. The pin 68 further functions toprevent pin 56 from rotating in the hole 58a, thus preventing pin 56from becoming misaligned relative to strip 35. Located within theannular space of the hole 58a and mounted between pin 68 and theshoulder 64 of pin 56 is a coil spring 70 for returning pin 56 from itsextended position. To move pin 56 to its extended position, the screw 62is screwed into housing 58 by means of a screw driver (not shown) orother similar conventional tool inserted into a saw kerf 72 provided inscrew 62. As the rotation of screw 62 is continued, the rotationalmovement of screw 62 is translated into linear movement of pin 56,causing pin 56 to be carried upwardly until the bifurcated portions 56aand 56b thereof extend sufiiciently beyond the lower end of strip 35..The bifurcated port-ions 56a and 56b in the extended position of pin 56,thus, in a sense, engage strip 35 to consequently permit only aninsignificant degree of lateral movement of thermal element TE. When itbecomes desirable to place the relay in service, the direction ofrotation of screw 62 is reversed and pin 56, under the influence ofspring 70, is backed off to a position in Which bifurcations 56a and561; no longer interfere with the movement of strip 35. It will beunderstood that screw 62 may be retained in housing 58 to prevent theentry of foreign substances into the housing.

By properly selecting the characteristics of spring 70 a considerablepressure may be applied to screw 62 at the point of its engagement withshoulder 64 of pin 56 at times when pin 56 is out of engagement withstrip 35. Maintaining the spring pressure on the driving screw will havethe effect of preventing externally caused vibration from graduallyloosening screw 62 and causing the screw to eventually escape from thehousing. This obviously has the advantage that the screw always remainsin position in the relay and is available for use at any time.

One advantage of holding means embodying my invention is that itprovides a simple and effective way for protecting the sensitive thermalelements of a thermal relay during shipment without aifecting thecalibration of the relay.

It is to be understood, of course, that my invention is not limited foruse only in connection with thermal relays, but is applicable in itsbroader aspects for use with various other types of relays andelectrical instruments in which it is desired to protect the sensitiveparts thereof during shipment.

Although I have herein shown and described a specific construction ofholding means as evidenced by the accompanying illustrations, I do notdesire to limit myself to the particular relation of their parts orother details of construction or arrangement, as various changes may bemade within the scope of the appended claims without departing from thespirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, an electrical instrument having an operating elementmovable between a normal position and an operated position, a supportmember fixed with respect to said element and provided at its one endwith a screw-threaded hole aligned with said element when said elementis in its normal position, a screw screwed into said screw-threadedhole, a locking pin slidably mounted in said member and biased to aretracted position in engagement with said screw and movable by saidscrew from its retracted position to a projected position adjacent tosaid element when said element is in its normal position, and means onthe free end of said locking pin for engaging said element to preventits movement when said locking pin is in its projected position and saidelement is in its normal position.

2. In combination, a relay having an operating element movable between anormal position and an operated position, a support member in said relayfixed with respect to said element and provided at its one end with afirst hole and provided at its other end with a second screw-threadedhole concentric with said first hole and in communication therewith,said first and second holes being in alignment with said operatingelement when said operating element is in its normal position, a screwscrewed into said screw-threaded hole, and a locking pin slidablymounted in said first hole and biased to a retracted position inengagement with said screw and movable by said screw from its retractedposition to a projected position in which the free end thereof engagessaid operating element when said element is in its normal position toprevent movement thereof.

3. In combination, a relay having an operating element movable between anormal position and an operated position, a support member fixed withrespect to said operating element and provided at its one end nearest tosaid operating element with a first hole and provided at its other endwith a second hole concentric with said first hole, a locking pinslidably mounted in said first hole and movable from a retractedposition spaced from said operating element to a projected position, adriving member adjustably mounted in said second hole and movable towardand away from said operating element, spring means caged in said firsthole for biasing said locking pin into engagement with said drivingmember, whereby when said driving member is moved away from saidoperating element said locking pin is urged by said spring means to itsretracted position, and means on the free end of said locking pin forengaging said operating element to prevent its movement when saidlocking pin is in its projected position and said operating element isin its normal position.

4. In combination, a relay having a cover and having a part movablebetween a normal position and an operated position, said cover having anopening therethrough in alignment with said part when said part is inits normal position, a support member mounted at one end in saidopening, said support member provided at said one end with ascrew-threaded hole aligned with said part when said part is in itsnormal position, a screw screwed into said screw-threaded hole, alocking pin at the other end of said support member slidably mounted insaid support member and biased to a retracted position in engagementwith said screw and movable by said screw from its retracted position toa projected position, and a bifurcation on the free end of said lockingpin arranged relative to said part such that the branches of saidbifurcation extend alongside the opposite sides of said part to preventits movement when said part is in its normal position and said lockingpin is in its projected position.

5. In a relay comprising a part movable between normal and operatedpositions and including a cover for said part, said cover having anopening therethrough in alignment with said part when said part is inits normal position, and means for holding immovable withinpredetermined limits said part for shipping purposes, said holding meanscomprising, in combination; a support member mounted at one end in saidopening and provided at said one end with a first hole extending to apoint outside said cover and provided at its other end with a secondhole concentric with said first hole, the diameter of said first holebeing less than the diameter of said second hole, a driving memberslidably mounted in said first hole and movable forwardly into saidsecond hole, a locking pin slidably mounted in said second hole andbiased to a retracted position in engagement at its one end with saiddriving member and movable from its retracted position by said drivingmember to a projected position in which the other end thereof engagessaid part when said part is in its normal position to prevent itsmovement, and means secured to said support member for preventing saidlocking pin from being ejected from said support member by said drivingmember during its forward movement.

6. In combination, an instrument having a part laterally movable betweena normal position and an operated position, a cover for said part havingan opening therethrough in alignment with said part when said part is inits normal position, an elongated housing in said instrument mounted atone end in said opening, said one end of said housing being providedwith a first hole accessible for entry from outside of said cover, theother end of said housing being provided with a second hole concentricwith said first hole and said second hole communicating with said firsthole, a locking pin slidably mounted in said second hole, a drivingmember slidably mounted in said first hole and movable toward and awayfrom said locking pin, spring means caged in said second hole andbearing on said locking pin for biasing said locking pin to a retractedposition in engagement with said driving member, said driving membereffective when moved toward said locking pin for carrying said lockingpin from its retracted position to a projected position, and means onthe free end of said looking pin for engaging said part to prevent itslateral movement when said locking pin is in its projected position andsaid part is in its normal position.

7. In a relay having a part movable between normal and operatedpositions in which movement of said part when it is in its normalposition is at times desired to be prevented, the combination comprisinga support member fixed with respect to said part and provided at its oneend with a screw-threaded hole accessible for entry from the exterior ofsaid relay and provided at its other end with a second hole concentricwith said screw-threaded hole and communicating therewith, a first pinsecured to said support member and diametrically disposed across themouth of said second hole, a second locking pin slidably mounted in saidsecond hole and provided with a projecting shoulder and provided at itsone end nearest to said part with a bifurcation the branches of whichproject alongside the opposite sides of said first pin therebypreventing said locking pin from rotating relative to said part, a screwthreaded in said screw-threaded hole, and spring means in said secondhole interposed between said first pin and said shoulder for yieldablybiasing said locking pin to a retracted position in which it bears onsaid screw, whereby when said part is in its normal position and saidscrew is adjusted a predetermined amount said locking pin is movedthereby from its retracted position to a projected position in whichsaid branches extend on the opposite sides of said part to prevent itsmovement.

References Cited in the file of this patent UNITED STATES PATENTS901,013 Knott Oct. 13, 1908 2,125,399 Sayre Aug. 2, 1938 2,351,097Boeringer June 13, 1944 2,371,018 Ashworth et al. Mar. 6, 1945 2,390,479Watson et al. Dec. 4, 1945 2,872,548 Christensen Feb. 3, 1959 2,965,747Secofsky Dec. 20, 19Q

